In PvE, theres always that one guy thats afk the whole game, or behave in toxic manner that the rest of the team would rather not deal with, adding the ability to vote kick players if theres more than 2-3 players in a game would be very helpful in improving the player experience with little negative impact on the performance of the game, or even the community.
@ubermarine Mikee, the man himself, has talked about this a bit.
Adding in a votekick system adds in another layer of trolling, honestly. Especially in Coop gamemodes with only eight players, I've been votekicked off of servers for zero reason whatsoever. Mikee was saying that if someone's acting really toxic, the best thing to do is just mute them from the scoreboard. Adding a feature to also hide their text chat could be neat, too.
That being said, you should be forgiven for teamkills far slower than you currently are. Right now, you can kill like 20 teammates over the course of the match and not get auto-kicked for it.
A feature seen in games like Red Orchestra 2 might be useful too, where if you're TK'd you can choose to forgive the TKer or not.